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Is there an easy way to make this OBJ have smooth surfaces?

14 REPLIES 14
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Message 1 of 15
Anonymous
17726 Views, 14 Replies

Is there an easy way to make this OBJ have smooth surfaces?

I am pretty new to F360, and even newer to mesh objects.  So please, bear with me.

 

I have an OBJ I have imported.  Here, the example I am using is simply a 5 sided box, representing a fabric like material glued or sewn together on the edges.  The project is attached here, and so is the original OBJ.

 

I want to be able to convert the faces into bodies so I can apply a fabric appearance.  I have gone through a bunch of tutorials and posts here, and I also installed Meshmixer, which I haven't figured out yet.  No matter what I do, the triangles remain and I can't apply appearance.  I also tried patching it, but patch won't even recognize the edges when I go to patch.  Then, if I share the link, the shared version looks even worse than the flat shaded as opposed to the smooth shaded version in F360.  Here is the link.  

https://a360.co/2CEHFTR

 

I really need to be able to import these OBJ files and make them look like fabric.  Is there a simple way to achieve this?  I truly appreciate any help anyone can offer.  I am running F360 on Mac 10.12.  Thank you.

 

The forum won't allow me to upload the OBJ file, I've uploaded it here.  http://s000.tinyupload.com/index.php?file_id=69433356251775717017

14 REPLIES 14
Message 2 of 15
norbertut
in reply to: Anonymous

Hi, to convert a Mesh to a body, you need to first disable "Capture Design History". You can do this if you select the top element of the object tree (filename component) and then right click. There's an option "do not capture Design History".

 

Once this is done you can use the function "Mesh to BRep" that creates a solid from your mesh (and then you can apply an appearance for the Fabric). Just right click on each mesh body and you can see the menu option.

 

For the box there is no issue, but usually when there are more than 10.000 to 15.000 triangles the application complaints and more than this it doesn't even let you convert it. No issue for the box example but it could be an issue for other projects you have (there are several mesh tools and you can also try to reduce mesh to lower the number of triangles).

 

Once you have the objects, in your case they are converted to surfaces (if it was a closed object it would be converted to a solid). I noticed in your box example the faces are inverted (normal is looking inside) so you need to reverse normal for each face. This can be done with the Patch workspace (command Modify-Reverse normal). Once everything looks fine you can then apply appearance to the bodies. If you want to have fabric appearance also inside then you need to convert these surfaces to solid. I would combine them to make one single body and then Create-Thicken to your desired thickness.

 

Regarding the smoothing, before converting to BRep you can edit a mesh and apply several operations. As stated before you can reduce mesh to have less triangles, you can remesh and more important for you, you can smooth the mesh. So before anything apply first this smoothing operation.

 

I have attached the box example converted to surfaces, with faces normals reversed and fabric material applied.

 

If this helps you please like it, and if it works as a solution please mark it accordingly. Helps me stay engaged with the forum Smiley Wink

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Message 3 of 15
TrippyLighting
in reply to: Anonymous

In one word. No!

 

What @norbertut has suggested is incorrect as when converting a triangulated mesh directly to a BRep :

1. in this case will not result in a solid but surfaces

2. will translate exactly the faceted nature of the mesh and will not be smooth.

 

Having said that, this object should not be so hard to re-create with a T-Spline in Fusion 360.

 

Is this close enough ?

 

Screen Shot 2018-12-30 at 8.39.11 AM.png


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Message 4 of 15
Anonymous
in reply to: norbertut

norbertut, 

That is what I tried before, but as TrippyLighting said, you can still see the facets. It's still not smooth.  I just tried to go through again and use the smooth mesh option, but I haven't quite figured it out yet.  I tried the smooth command before mesh to brep, and after.  On brep, it won't select any faces, so I tried creating faces, and it still didn't work.  Then, I tried it on the mesh object as imported and it only allows me to select faces by selecting each individual facet.  In this case, from the inside of the box, because it won't yet let me reverse normal on the mesh object.  It will allow paint selection or window selection, but only in one go.  Once I let go of the click, to orbit, for example, it won't let me add any more facets to my selection.  Two times I managed to paint a whole face selection and on smoothing, F360 crashed.  Am I doing it wrong?  My real projects are going to be far more intricate than this box, so I am starting to feel this is not a viable solution for me.  But I'm more than willing to try until I get it right before I judge.  So I appreciate the help and will keep at it.  Unfortunately, without smoothing, it still looks very "facety" (is that even a word?).  

 

TrippyLighting,

I appreciate your straight forward answer on "No".  I did ask if there is an easy way to do this, because it has to be part of a workflow that will be done over and over again.  The simple truth is, my reason for this particular request is that I really just want to use F360's share public link to allow my clients to see a model that I am creating in other software.  That software has a similar feature, but it is very buggy, slow and unintuitive.  I am using F360 for some of the model components and currently importing them into the other software, but figured it would be better to go the other way and use F360 to share the model.  I anticipate client review and changes requested many times before a model is complete.  If I have to go through the above process every time I make a little change, it will take me longer to upload the model than it will to make the changes, and my workflow will be too tedious.  So it's looking like I may need to abandon this idea. 

 

I really appreciate the advice from both of you, but I think this may be unsolvable because the answer seems to be that no, there is not an easy way to do this workflow.

Message 5 of 15
norbertut
in reply to: TrippyLighting

Hi, @TrippyLighting, I think you went through my reply quite fast...

 

For your first point, I stated:
"Once you have the objects, in your case they are converted to surfaces (if it was a closed object it would be converted to a solid)."

 

For second point, I was also suggesting to smooth the mesh before converting to BRep.

 

I agree with you it is difficult to modify an OBJ and it is often better to draw from scratch, but the box was just an example of a workflow @Anonymous is trying to put in place.

Message 6 of 15
norbertut
in reply to: Anonymous

As @TrippyLighting explains, even if you smooth it or remesh it, you can get to smaller triangles and lower the faceted aspect, but there still will be triangles so it's never going to be a smooth surface.

 

Regarding the operations in Mesh workspace, you can select the whole mesh when you apply the operation instead of selecting by facets. Just click on the mesh body in the object browser.

 

Message 7 of 15
TrippyLighting
in reply to: norbertut


@norbertut wrote:

Hi, @TrippyLighting, I think you went through my reply quite fast...

 

For your first point, I stated:
"Once you have the objects, in your case they are converted to surfaces (if it was a closed object it would be converted to a solid)."

 

For second point, I was also suggesting to smooth the mesh before converting to BRep.

 

I agree with you it is difficult to modify an OBJ and it is often better to draw from scratch, but the box was just an example of a workflow @Anonymous is trying to put in place.


1. That is probably true 😉

2. How do you propose to "smooth" a triangulated mesh ?

 

 

I will continue to refer to "triangulated mesh" instead off a particular file extension.

The .obj format is perfectly fine to transport high quality quad meshes, textures (not used by Fusion 360) etc.

 


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Message 8 of 15
Anonymous
in reply to: norbertut

norbertut, I'm not giving up on your recommendation yet.  I'm working on it right now.  

 

TrippyLighting,

I forgot to mention, although I think it should have become clear....  Recreating the model is not an option because I am needing a workflow to use regularly, not a workaround to use on this box.  My models will be for bigger, more complicated and harder to reproduce.  But I did appreciate the idea you provided based on the information I provided.  It just won't be a solution for a good workflow to make every model twice.  

Message 9 of 15
TrippyLighting
in reply to: Anonymous

@Anonymous you workflow needs an update if your other software can only export triangulated garbage.

 

@norbertut the entire purpose of re-meshing is to create quad-mesh topology. That will import and convert fine into a T-Spline in Fusion 360. I use this process all the time and have demonstrated numerous times how that can be done.


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Message 10 of 15
Anonymous
in reply to: TrippyLighting

Okay, I've had some time to research and tinker.  I found a great trick from another user on how to convert this mesh.  Here is the current result.  

https://a360.co/2F1qQUD

 

This is the method used    https://www.youtube.com/watch?time_continue=339&v=8qTx_9HK7IM

But now the new problem I have is that I have lost my 5 individual faces.  Is there something I could do differently to make this process keep the faces?  I can't go in and split it every time I make a revision.  And is there anything I could do to smooth the patchy surface?  

 

Hey, at least Im trying, and at least it's not triangle garbage anymore.  

Message 11 of 15
TrippyLighting
in reply to: Anonymous

I could have done the same with Instant Meshes. The matter is, however, all of the re-meshing methods will require some form of manual work afterwards.

 

I am still wondering what other software you are using that creates only triangulated meshes as output.


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Message 12 of 15
norbertut
in reply to: TrippyLighting


@norbertut the entire purpose of re-meshing is to create quad-mesh topology. That will import and convert fine into a T-Spline in Fusion 360. I use this process all the time and have demonstrated numerous times how that can be done.


@TrippyLighting

Do you have a link or suggest where to search to find some of these examples? I went through your profile and there are plenty of screencasts, but didn't handle how to look for this specific case.

Would be glad to go through it.

Thanks!

Message 13 of 15
Anonymous
in reply to: TrippyLighting


@norbertut wrote:

@TrippyLighting

Do you have a link or suggest where to search to find some of these examples? I went through your profile and there are plenty of screencasts, but didn't handle how to look for this specific case.

Would be glad to go through it.

Thanks!

This seems to be an issue for me too.  While I appreciate the quick replies, they were a little too vague for me.  Looking back, I now see that you did use a few key words that I could have focused on to lead me the right way, but it was too cryptic because of my lack of knowledge on the subject.  I get that whole "it's better to teach a man to fish than give him a fish" thing, but I had to spend two days rebuilding my PC to get a Windows system running to do the Photo Recap test.  In the future, a little more straight forward answer would be helpful.  I do appreciate your participation in my post, though.  I have actually followed a lot of your advice on this board from other posts and you have already given me a few good lessons before this post!

 

@TrippyLighting wrote:

I could have done the same with Instant Meshes. The matter is, however, all of the re-meshing methods will require some form of manual work afterwards.

 

I am still wondering what other software you are using that creates only triangulated meshes as output.


 

I wasn't familiar with Instant Meshes until you provided the link.  I would check it out, but you opened up my curiosity and solved my problem without even knowing it.  You questioned why I couldn't export in quads, and I wondered the same thing.  I did some searching and found out that I can!  It was a setting in a completely different toolbox than I expected something like that to be in, nowhere near the export settings.  The dropdown it's under is labeled "miscellaneous".  If I didn't search for it, I don't know when I would have actually found that.  So, I was able to export in quads and I now have my problem solved.

 

Although my problem is solved, I have to leave my original question as unsolvable because Fusion 360 does not have an easy solution to do what I originally wanted.  

Message 14 of 15
TrippyLighting
in reply to: Anonymous


@Anonymous wrote: 

Although my problem is solved, I have to leave my original question as unsolvable because Fusion 360 does not have an easy solution to do what I originally wanted.  


You can mark this as solved. There is no easy solution for converting triangulated meshes into quad meshes.

This is a mathematical reality in any 3D software, whether it's a Sub-D modeling, NURBS modeling or CAD software.

I've done this stuff for almost 30 years and you can safely assume that I have a pretty good understanding of the matter.

 

Quad meshes when used as control point meshes as is the case in Sub-D modeling, T-Spline and PolyNURBS modeling have a topology and with T-Splines and PolyNURBS being able to create resolution free, mathematically precise surfaces.

 

The mathematical precision is lost when a surface is triangulated into a fixed resolution mesh and the object looses its topology. In essence there is a significant loss of information when going from a NURBS model to a triangulated object. That information cannot be fully re-created even with re-meshing and other reverse engineering software. It can only be approximated.

 

Complex math does not have easy buttons!


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Message 15 of 15
Anonymous
in reply to: TrippyLighting

Great explanation!  Now I actually understand a lot more about why these conversions are difficult to do in the back end of the software, and why they don't work as well as I was hoping.  It makes much more logical sense now.  I guess I assumed that since these conversion tools are available, there was something I could have done to make my format better setup for the tools to get a better result.  I see now that due to logical limitations, these tools are really more for a different purpose, like doing a bunch of the work for you to save time, not really to do all the work for you.  Again, it just makes sense.  And I assume there are some situations where these conversions probably do most of, it not all the work just fine.  Just not in my case. 

 

Thanks for the assistance @norbertut and @TrippyLighting

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